Kwok Tung Lee

Angioplasty and Stenting of Atherosclerotic Middle Cerebral Arteries with Wingspan: Evaluation of Clinical Outcome, Restenosis, and Procedure Outcome

BACKGROUND AND PURPOSE: MCA is a common location of intracranial stenosis. It is relatively more peripherally located and of a smaller caliber, and could therefore be a site technically more challenging and risky for angioplasty and stenting. The study aimed to evaluate the clinical outcome, restenosis rate, and procedural safety of Wingspan stent placement for atherosclerosis in the MCA compared with stenosis in other arteries. MATERIALS AND METHODS: Patients who underwent Wingspan stent placement for symptomatic intracranial stenosis of ≥70% (or stenosis of ≥50% for recurrent ischemia despite medical therapy) were recruited prospectively and allocated into a study group (MCA stenosis, n = 35) and a control group (other stenosis, n = 25). Primary end points were the following: 1) all stroke or death rate at 1 year, and 2) significant in-stent restenosis rate at 1 year. Secondary end points were the following: 1) periprocedural complications within 24 hours, rate of TIA during the procedure, all stroke or death rate within 30 days; and 2) the inability to complete the procedure due to technical problems. RESULTS: Results of study group versus the control group were the following: degree of stenosis, 78.4 ± 10.9% versus 72.5 ± 11.2% (P value = .0456); diameter of stenosis, 0.6 ± 0.3 versus 1.0 ± 0.5 mm (P = .0017); all stroke or death rate at 1 year, 14.3% versus 12% (OR = 1.22); in-stent restenosis rate at 1 year, 10% versus 10.5% (OR = 1.05); periprocedural complication rate at 24 hours, 2.9% versus 4% (OR = 0.70); TIA rate during the procedure, 8.6% versus 4% (OR = 2.25); all stroke or death rate at 30 days, 5.7% versus 12% (OR = 0.44); and technical failure rate, 2.9% versus 0%. CONCLUSIONS: In this study, there were no significant differences in procedural safety, patient outcome, and restenosis rates of stent placement between the group with MCA stenosis and the group with stenoses located at other sites.

Learning curve of Wingspan stenting for intracranial atherosclerosis: single-center experience of 95 consecutive patients

Background Symptomatic brain hemorrhage was a significant cause of periprocedural stroke or death following stenting in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis trial, which called into question the safety of Wingspan stenting for intracranial atherosclerosis. This study analyzed the role of a learning curve in the safety and outcome of Wingspan stenting from the experience of 95 consecutive patients at a single center. Methods In this prospective study the endpoints were major stroke or death (modified Rankin Scale score >3) within 30 days, other neurological complications, technical procedural problems, technical success in completion of angioplasty and stenting and recurrent ischemic stroke in the corresponding vascular territory after 30 days. Data splitting into quarters was used for learning curve analysis. Results The periprocedural major stroke or death rate was 4.2% (4/95), minor stroke rate was 5.3% (5/95), total 9.5% (9/95). The technical procedural problem rate was 11.6% (11/95) and the technical success rate was 93.7% (89/95). The 89 patients were followed for 38.9±22.7 months (median 40.8, range 0.2–72, 3463 patient-months) after stenting. The risk of recurrent ischemic stroke in the corresponding vascular territory was 0.7% per patient per year (2/3463 patient-months). Guidewire- or angioplasty-related hemorrhage was the major cause of periprocedural major stroke or death (3/4, 75%) and did not occur in the last quarter. Periprocedural intracerebral hemorrhage was uncommon and perforator stroke did not occur. Conclusions There may be a learning curve for mastering the safety precautions of Wingspan stenting for intracranial atherosclerosis.

Angioplasty and stenting of intracranial atherosclerosis with the Wingspan system: 1-year clinical and radiological outcome in a single Asian center

Background This study aimed to evaluate the 1-year clinical and angiographic outcome of angioplasty and stenting of intracranial atherosclerosis using Wingspan and Gateway system. Methods In this prospective study, patients with symptomatic lesions were treated and followed clinically and angiographically by digital subtraction angiography (DSA) for 1 year. The two primary endpoints were recurrent ipsilateral ischemic stroke and in-stent restenosis (ISR) at 1 year. Secondary endpoints included periprocedural death or stroke and all strokes at 1 year. Potential factors correlated with ISR were studied using univariate and multivariate analysis. Results Treatment was attempted in 65 patients and successfully completed in 61 (93.8%). Fifty-nine patients (44 men, 15 women) aged 62.86±11.38 years with 66 stenoses (average degree of stenosis 71.78±11.23%) underwent clinical and DSA follow-up at 1 year. There were 66 stenotic lesions. ISR occurred in 11 of the 66 lesions (16.7%). Luminal gain occurred in 32 of the lesions (48.5%), an unchanged lumen in 4 (6%) and luminal loss in 30 (45.4%). The periprocedural stroke or death rate was 6.1% (4/65), including three hemorrhagic and one ischemic stroke, all of which occurred at the corresponding site and resulted in death. There were no interval strokes between the periprocedural time and the 1-year follow-up. The occurrence of ISR was correlated with the degree of stenosis before treatment and was not correlated with patient age or sex, vessel diameter, location of stenosis or failure to control risk factors for atherosclerosis. Conclusions One-year clinical and angiographic outcomes of angioplasty and stenting are promising for symptomatic intracranial atherosclerosis.

Evaluation of Carotid Angioplasty and Stenting for Radiation-Induced Carotid Stenosis

Background and Purpose— We aimed to evaluate the procedural safety, clinical, and angiographic outcome of carotid angioplasty and stenting for high-grade (≥70%) radiation-induced carotid stenosis (RIS) using atherosclerotic stenosis (AS) as a control. Methods— In this 6-year prospective nonrandomized study, we compared the carotid angioplasty and stenting outcome of 65 consecutive patients (84 vessels) with RIS with that of a control group of 129 consecutive patients (150 vessels) with AS. Study end points were 30-day periprocedural stroke or death, ipsilateral ischemic stroke, technical success, procedural characteristics, instent restenosis (ISR; ≥50%) and symptomatic ISR. Results— The median follow-up was 47.3 months (95% confidence interval, 26.9–61.6). Imaging assessment was available in 74 vessels (RIS) and 120 vessels (AS) in 2 years. Comparing RIS group with AS group, the rates of periprocedural stroke or death were 1.5% (1/65) versus 1.6% (2/129; P=1); ipsilateral ischemic stroke rates were 4.6% (3/65) versus 4.7% (6/129; P=1); the annual risks of ipsilateral ischemic stroke were 1.2% (3 patient/254.7 patient year) versus 1.2% (6 patient/494.2 patient year; P=0.89); technical success rates were both 100%. Stenting of common carotid artery and the use of multiple stents was more common in the RIS group (P=0 in both cases); ISR rates were 25.7% (19/74) versus 4.2% (5/120; P<0.001); symptomatic ISR rates were 6.8% (5/74) versus 0.8% (1/120; P=0.031). Conclusions— The safety, effectiveness, and technical difficulty of carotid angioplasty and stenting for RIS are comparable with that for AS although it is associated with a higher rate of ISR. Clinical Trial Registration— This trial was not registered as enrollment started in 2006.

Angiographic Features, Collaterals, and Infarct Topography of Symptomatic Occlusive Radiation Vasculopathy A Case-Referent Study

Background and Purpose— Occlusive radiation vasculopathy (ORV) predisposes head-and-neck cancer survivors to ischemic strokes. Methods— We analyzed the digital subtraction angiography acquired in 96 patients who had first-ever transient ischemic attack or ischemic strokes attributed to ORV. Another age-matched 115 patients who had no radiotherapy but symptomatic high-grade (>70%) carotid stenoses were enrolled as referent subjects. Digital subtraction angiography was performed within 2 months from stroke onset and delineated carotid and vertebrobasilar circulations from aortic arch up to intracranial branches. Two reviewers blinded to group assignment recorded all vascular lesions, collateral status, and infarct pattern. Results— ORV patients had less atherosclerotic risk factors at presentation. In referent patients, high-grade stenoses were mostly focal at the proximal internal carotid artery. In contrast, high-grade ORV lesions diffusely involved the common carotid artery and internal carotid artery and were more frequently bilateral (54% versus 22%), tandem (23% versus 10%), associated with complete occlusion in one or both carotid arteries (30% versus 9%), vertebral artery (VA) steno-occlusions (28% versus 16%), and external carotid artery stenosis (19% versus 5%) (all P<0.05). With comparable rates of vascular anomaly, ORV patients showed more established collateral circulations through leptomeningeal arteries, anterior communicating artery, posterior communicating artery, suboccipital/costocervical artery, and retrograde flow in ophthalmic artery. In terms of infarct topography, the frequencies of cortical or subcortical watershed infarcts were similar in both groups. Conclusions— ORV angiographic features and corresponding collaterals are distinct from atherosclerotic patterns at initial stroke presentation. Clinical decompensation, despite more extensive collateralization, may precipitate stroke in ORV.

Angioplasty and stenting for intracranial atherosclerotic stenosis with nitinol stent: factors affecting technical success and patient safety.

BACKGROUND: Angioplasty and stenting using nitinol stents is a recognized treatment option for intracranial atherosclerosis. OBJECTIVE: To identify procedure-related factors that may affect patient safety and technical outcome. METHODS: In this prospective study of 57 consecutive patients, the primary end points were intraprocedural technical problems, periprocedure morbidity, and complications. Major periprocedure complication was defined as all stroke or death at 30 days. Technical failure was defined as the inability to complete the procedure because of technical or safety problems. Procedure failure was defined as a procedure outcome of technical failure or major periprocedure complication. Secondary end points were procedure-related factors that may affect patient safety and technical outcome. RESULTS: Procedure failure rate was 12.3% (7/57) (major periprocedure complication rate, 5.3% [3/57]; technical failure rate, 7% [4/57]). Initial failure in tracking of balloon or stent occurred in 20 patients, other technical problems occurred in 11 patients, including kinking or trapping of balloon catheter (2 cases), difficulty in unsheathing of stent (3 cases), forward migration of stent during deployment (4 cases), trapping of nose cone after stent deployment (1 case), fracture of delivery system (2 cases), and guidewire fracture (1 case). Unfavorable vascular morphology signified by the presence of 2 or more reverse curves along the access path was found to associate with initial failure in the tracking of instruments (OR = ∞), and occurrence of other technical problems (OR = 25). CONCLUSION: Procedure-related factors could be identified and lead to improvements in patient safety and technical outcome. Tortuous vascular morphology is a key factor to be overcome.

Intravenous C-Arm Conebeam CT Angiography following Long-Term Flow-Diverter Implantation: Technologic Evaluation and Preliminary Results

BACKGROUND AND PURPOSE: A noninvasive investigation with high spatial resolution and without metal artifacts is necessary for long-term imaging follow-up after flow-diverter implantation. We aimed to evaluate the diagnostic value of conebeam CT angiography with intravenous contrast enhancement in the assessment of vascular status following implantation of the Pipeline Embolization Device and to analyze the preliminary results of vascular status following long-term Pipeline Embolization Device implantation. MATERIALS AND METHODS: This was an ongoing prospective study of consecutive patients with intracranial aneurysms treated with the Pipeline Embolization Device. Patients with a modified Rankin Scale score of 4–5 were excluded. The median and interquartile range of the time interval of Pipeline Embolization Device implantation to conebeam CT angiography with intravenous contrast enhancement were 56.6 and 42.9–62.4 months, respectively. Conebeam CT angiography with intravenous contrast enhancement was performed with the patient fully conscious, by using a C-arm CT with a flat panel detector. RESULTS: There were 34 patients and 34 vascular segments. In all 34 cases, contrast effect and image quality were good and not substantially different from those of intra-arterial conebeam CTA. Metal artifacts occurred in all 14 cases with coil masses; the Pipeline Embolization Device was obscured in 3 cases. In all 34 cases, there was no residual aneurysm, no vascular occlusion, 1 vascular stenosis (50%), good Pipeline Embolization Device apposition to the vessel, and no Pipeline Embolization Device–induced calcification. All 28 Pipeline Embolization Device–covered side branches were patent. CONCLUSIONS: Conebeam CT angiography with intravenous contrast enhancement is potentially promising and useful for effective evaluation of the vascular status following intracranial flow diverters. The Pipeline Embolization Device for intracranial aneurysms is probably safe and promising for long-term placement, with favorable morphologic outcome and without delayed complications.

A compartmentalized volumetric system for outcome analysis of coiled cerebral aneurysms: aneurysm-coil mass-neck outcome assessment system.

OBJECTIVECurrent methodologies for outcome assessment of coiled cerebral aneurysms are based on rough estimations. The aim of this study was to develop a system of quantitative analysis for objective and accurate assessment of the outcome of cerebral aneurysms treated with coil embolization. METHODSThe quantitative analysis system is based on a concept of a perfect vessel tube and compartmentalized analysis of a coiled aneurysm. Based on the volumetric data of 3-dimensional radiographic angiography of the aneurysm and its associated parent vessel, a 2-step volume extraction method, including a global thresholding method and an augmented vessel method, is used for volume calculation. The coiled aneurysm (A) is compartmentalized into 2 volumetric components for quantitative analysis: 1) the volume of the coil mass (C), and 2) the volume of the uncoiled neck of the aneurysm (N). Changes in the volumetric data of the compartments A, C, and N at the time of follow-up provide a basis for outcome analysis. To test the clinical applicability of the system, the volumetric data for 21 consecutive cases of cerebral aneurysms in which a residual or recurrent cavity at the neck region was noted at the time of the 6-month follow-up evaluation were assessed with the aneurysm-coil mass-neck (ACN) outcome assessment system. RESULTSThe results of the outcome analysis of the 21 cases according to the ACN system correlated well with angiographic assessment of treatment outcome. CONCLUSIONThe ACN outcome assessment system is a useful diagnostic instrument for objective and accurate assessment of the outcome of cerebral aneurysms treated with coil embolization.

Long-Term Evolutionary Change in the Lumen of Intracranial Atherosclerotic Stenosis Following Angioplasty and Stenting

BACKGROUND Angioplasty and stenting is a recognized treatment option for patients with intracranial atherosclerosis. OBJECTIVE To evaluate the long-term evolutionary luminal changes of intracranial atherosclerosis after angioplasty and stenting. METHODS This was a retrospective study with patient consent. Eighty-two patients presenting with acute and minor cerebral ischemia due to stenosis ≥70%, who had received medical therapy with or without stenting (Wingspan), were invited. Luminal imaging was provided using 3-dimensional rotational angiography (3-DRA) at baseline and 12 mo, and cone-beam computed tomography angiography with intravenous contrast (CBCT) was provided at follow-up (median 82.4 mo [interquartile range 61.9-96.9 mo]). RESULTS Thirty-six patients in the stenting group and 26 patients in the medical group were recruited and completed the study. There was no statistically significant difference in demographics between the 2 patient groups. The luminal gain at 12 or 80 mo as compared to baseline in the stenting group was significantly greater than that in the medical group (12 mo: median gain 30% vs 7.2%, P < .001; 80 mo: median gain 42.9% vs 7.2%, P < .0001). Luminal loss or unchanged lumen was correlated with recurrent ischemic event. The differences in the stenosis degree assessment between CBCT and 3-DRA in the same 10 patients with or without stenting were 1.2 ± 0.6% or 0.2 ± 0.06%, respectively. There was a correlation between recurrent ischemic events and luminal loss. CONCLUSION Arterial lumen after angioplasty and stenting can probably be well maintained and delayed luminal gain does occur, long-term luminal loss is associated with recurrent ischemic events, CBCT might be useful as a less-invasive means for long-term assessment.